This invention relates to disc brakes and, particularly, to disc brakes having a friction pad wear warning device.
It is necessary to exchange friction pads of a disc brake when the wear of friction materials of the friction pads exceeds a predetermined amount so as to safely operate a vehicle. However, it is difficult for typical drivers to timely inspect the friction pads to note that the friction pads should be changed. Moreover, at times, the friction pads are not changed until the friction materials thereof have completely worn away and the braking force has been decreased substantially due to e.g. the metal-to-metal contact between the disc and the backing plate of the friction pad.
Accordingly, various types of friction pad wear warning devices have been proposed for detecting the wear of the friction pad and generating a warning signal when the amount of wear of the friction pad exceeds a predetermined amount thereby notifying the driver of the vehicle that the friction pad should be changed. There are problems in conventional friction pad wear warning devices generating the warning signals electrically or mechanically such that the construction thereof is complicated or that the devices do not operate reliably.